Chemical structure of vinyl alcohol/acrylamide graft copolymers prepared by the cerium(IV) ion method

Graft copolymerization of acrylamide onto poly(vinyl alcohol) (PVA) samples with different 1,2‐diol content was carried out by the Ce(IV) ion method. The poly(acrylamide) (PAAd) side chains were separated by oxidative degradation of the PVA backbone with nitric acid at which treatment the PAAd side chains reacted to poly(acrylic acid) (PAA) chains without a change of the degree of polymerization. The chemical structure of the graft copolymers was clarified on the basis of the number average molecular weights of the pure graft copolymer, of separated branches, and of the mother PVA molecules and the chemical composition of the graft copolymers. It was found that the number of branches per molecule was greater than one and increased with increasing content of 1,2‐diol structures in the PVA mother molecule. A number of grafted branches as high as 12 caused the graft copolymer to be insoluble in water.